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Philco 40-180 Tracking Issue
#1

Hi,

First time poster.  Thanks for the great site.

I just completed my first restore of a Philco 40-180 that I picked up on Craigslist.  I've always liked the design of the 40-180 and 40-190.  The cabinet restore turned out pretty good for my first try.  I replaced all caps, any resistors that needed replaced, and any wiring that needed to be replaced.  I have not replaced any tubes other than a 41 and rectifier that without question were dead (no light up) via another 41-280 dead chassis I picked up for parts and a needle that was missing from mine. The tubes I did replace were identical.

I followed Ron's procedure on the proper rocking of the adjustable caps at 1400 and 580 and followed the Philco alignment procedure.  I have a B&K 2500 generator with an HP freq counter and a Fluke VM.  In summary, during the alignment, IF had no issue.  I tuned for 455 kHz and had about 190V off of PIN 6 of the 1232.  I then went to SW 18 Mhz and peaked on the second carrier (primary) from the starting CW position slowly to CCW per the Philco procedure.  I then went to 1400 kHz and rocked and had no issue.   My issue comes with 580.  I can't get cap 19 to tune that high.  If I put the needle at 580 and the test generator at 580, I can't get 19 to peak any higher than about 565 kHz.  Regardless, I followed peaked at 565 and followed Ron's rock procedure and I do believe the radio is performing very well after the overhaul.  I'm picking up 620 in Canada here in Chicago, 590 in Omaha, and of course the locals are blasting in.  My only issue is the dial is off from approx 550-1000.  1000-1400 is slowly curves to normal At 1400 and above, it's spot on.  I didn't track SW, but I'm picking up stations.

I realize these are old radios, but given the lower end of the scale is very spread out and the upper is not, it seems silly to tune to 580 to hear WIND-560AM.  Given this 1939 is about 95% of the way there, I'd like to trim this in.  I don't want to simply shift the needle and find the happy medium.

Thoughts?  Looking at the schematic, there doesn't appear to be anything I can cheat to help the trim cap 19.  Could the OSC tube be weak?  Worth a swap?

Thanks for any help you can give.


Messages In This Thread
Philco 40-180 Tracking Issue - by tvmicrowave2002 - 10-09-2016, 03:52 AM
RE: Philco 40-180 Tracking Issue - by klondike98 - 10-09-2016, 08:44 AM
RE: Philco 40-180 Tracking Issue - by Radioroslyn - 10-09-2016, 09:48 AM
RE: Philco 40-180 Tracking Issue - by Radioroslyn - 10-09-2016, 12:57 PM
RE: Philco 40-180 Tracking Issue - by Radioroslyn - 10-09-2016, 03:56 PM
RE: Philco 40-180 Tracking Issue - by Radioroslyn - 10-10-2016, 12:48 AM



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